Manufacture of sugar



July 19, 1932. E. R. RAMSEY ET AL MANUFACTURE OF SUGAR Filed May 8, 19263 Sheets-She t INVENTOR WI wn/ $5 ATTORN EYS J y 1932- E. R. RAMSEY ETAL 1,868,472

MANUFACTURE OF SUGAR Filed May 8, 1926 3 Sheets-Sheet 2 y 1932- E. R.RAMSEY ET AL 1,863,472

MANUFACTURE OF SUGAR Filed May 8, 1926 3 Sheets-Sheet 3 INVENTOR BYW L0,M IZM'Q, 0% W ATTORNEYS Patented July 19, 1932 UNITED STATES PATENToFFIcE ELMER R. RAMSEY, OF DENVER, COLORADO, AND ARTHUR W. BULL, OFWESTPORT,

CONNECTICUT, ASSIGNORS, BY MESNE ASSIGNMENTS, TO THE DORR COMPANY,

INC., OF NEW YORK, N. Y., A CORPORATION OFDELAWARE MANUFACTURE OF SUGARApplication filed May 8, 1926. Serial No. 107,579.

This invention relates to the manufacture of sugar. It is moreparticularly directed to the automatic control of they treatment processof sugar-bearing juices, such as beet or cane, employed in themanufacture of sugar; although the principles of the invention may alsobe employed with advantage in other treatment processes.

In treatment processes of numerous kinds, it has long been desirable touse a conveniently applicable method and apparatus for conducting thetreatment operation within definite, prescribed, and desired limitswhich can be automatically controlled. It is also of advantage that suchoperations be conducted in a continuous manner, rather than in the moreusual batch fashion. Our discovery makes such a practice possible,because by the improved method and apparatus of this invention we areable to readily conduct the treatment operation under automaticallycontrolled conditions in such manner that the materials going into thetreatment process emerge at the end of their reaction Within definitelyprescribed limits of content.

Again, it is also highly desirable that such preliminary automaticcontrol of the treatment process be carried out in such manner that thesubsequentsteps in the treatment process may be more efiicientlyconducted. We are able to do this as will be hereinafter moreparticularly pointed out.

Briefly and in its broader aspect, our invention comprises a method andapparatus for securing an action responsive to changes in a-variablecomponent of the treatment process at a point removed from the zone ofactive reaction, and utilizing said action to automatically vary thecontent of said component to predetermined limits.

Our invention will be better understood by reference to its successfuluse in the manufacture of sugar, particularlv in the preliminarytreatment of sugar-bearing liquids wit gases, as in the firstcarbonation step of the standard purification process, and then in thesubse uent treatment of the carbonated juices where y a separation ismade between thesolids and the juices.

Briefly stated, the operations involved in the manufacture of sugar frombeet root are as follows: (a) extraction of the juice from the beetroot; (1)) clarification of the juices; (0) concentration of the juiceto sirup; (d) crystallization of the sugar from the sirup; (6)separation of the crystals; and (f) treat ment of the separated sirupfor the working up of the after-products.

Our invention is more particulary directed towards the operation dealingwith b) clarification of the juices. The first operation above referredto, (a) extraction of the juices from the beet root, is generallycarried on in so called diffusion batteries. {When the diffusion juiceleaves the battery it is cloudy and contains in solution or suspensionthe soluble constituents of the beet, namely, sucrose, potassium andsodium salts of phosphoric, sulphuric, hydrochloric, oxalic, andtartaric acids, proteins, pectins, etc., and a small amount of invertsugar. In reaction it is slightly acid.

In order to separate the suspended fibre, cellular tissue, andcoagulated albumen, the juice is subjected to pulp-separation. The juiceis then heated, to about 85 0., which has the effect of coagulating aportion of the albumen present, besides preparing it for clarification.4

In the beet sugar factory, clarification is generally carried out in twostages: in the first, known as defecation or liming, milk of lime,Ca(OH) is added to the heated juices; and in the second, known ascarbonation, the lime, Ca(OH) is removed by precipitation as CaCO withcarbon dioxide (00,) gas.

After liming (defecation), the juice is ready for the second stage ofthe clarifying operation, namely, carbonation or saturation with carbondioxide gas, in which the lime is precipitated. Small amounts of mineral and organic matter are also thrown down. The original slightly acidbeet juices become alkaline by the addition of an excess of lime duringthe limin operation. Itis desirable to reduce the al alinity to certainlimits by correct additions of CO in the carbonation step.

lit

The carbonated materials are then subjected to continuous thickening toseparate the clear juice from the sludge. The slud e from the thickeningoperation is next su jected to continuousfiltering, whereby theremaining clear juices are efliciently separated from the undesirablesolids.

If the clarifying steps have been well conducted, the resultant clearjuices are then in condition for the subsequent operations of sugarmaking, steps a, d, e, and f, as outlined above. Heretofore accurate anddependable control of the alkalinity of the'carbonated juices withinpredetermined desired limits has been dificult of attainment. This iseven true in the more common practice of treatment of batches of thejuices, and is more ,particularly true in attempted continuous teriallyaids in the subsequent separation of (ill the solids from the clear enar juices.

Moreover the dependence on hand control of skilled carbonators isdispensed with.

In our present ractice of the invention constant volumes 0 preheatedbeet juices and lime solutions are automatically flowed together intothe first of a series of carbonating vessels. Suitable pumps areemployed for this purpose. An excess of lime is employed which throwsthe slightly acid beet juice over into the alkaline state. i

' A carbon dioxide bearing gas, preferably under regulated pressure, isinjected into the body of limed juices on the counter-current principle.That is to say, the limed juices flow downwardly as the injected carbondioxide gas rises upwardly from near the bottom of the carbonationtanks. The alkalinity is somewhat reduced as the lime precipitates inthe form of calcium'carbonate.

The preliminarily carbonated juices are then led to a second carbonatorfor a further treatment with carbon dioxide gas. It may here be pointedout that we have quite satisfactorily employed as many as threecarbonators in series, as well as only one carbonator. However, weprefer to make use of but two carbonators in series. The foam generatedin the first carbonator passes from the top of the first carbonator tothe top of the second carbonator, whereas the carbonated limed juicepasses from the bottom of the first carbonator to the juice level of thesecond carbonator.

A portion of previously carbonated juice, containing precipitatedcalcium carbonate, may be recirculated from the bottom of the secondcarbonator tank and led into the top of the first carbonator tank. Theparticles of calcium carbonate then tend to encourage particle growth asthey pass toward the bottom of the carbonating vessel.

Automatically controlled amounts of carbon dioxide gas are passed intothe already partially carbonated juice in the second carbonator to bringthe juice within predetermined limits of alkalinity. This automaticallycontrolled feature is made to depend upon the electrical resistanceoffered b the treated juices, coming from the last car onator, betweensuitable electrodes appropriately immersed in the liquid at a pointremoved from the zone of active reaction of the carbon dioxide gas onthe limed juices. tant to measure this electrical resistance at a pointbeyond all further reaction of the added ingredients, else theelectrical resistance cannot be regarded as a true criterion from whichto automatically control the end point. The electrical resistance of thematerials is apparently substantially unafi'ected by the purity,concentration of the su ar juices, or the presence of precipitated soids. On the other hand, the concentration of dissolved lime, which isthe measure of alkalinity, appears to be the predominatin factor. Hence,the electrical resistance will vary as the concentration of dissolvedlime varies. There is an almost constant parallelism between alkalinityand electrical conductivity.

It is essential that the electrical resistance be measured after thechemical and dissolution reactions have been completed. In thecarbonation tanks the reaction of carbon dioxide gas on dissolved'limetakes place so rapidly that the concentration of lime in true solutionis reduced below the value it would have if the gas were momentarily cutoil and the remaining undissolved lime were allowed to pass intosolution. For this reason we place the electrodes in a continuallyflowing stream of juice at some distance from the carbonation tanks sothat complete solution of soluble lime will have occurred before thejuice reaches the electrode chamber.

The permissible limits of alkalinity are 0.07 to 0.13 measured in gramsof CaO per 100 cc. of filtered juice. We have been able to make longcontinuous runs in which the alkalinity was maintained within the verynarrow and highly desirable range of 0.09 to 0.11'grams of C20 per 100cc. of juice.

The control or standard resistance (one resistance arm of a'Wheatstonebridge, as will be more fully explained below) may be set to correspondwith an alkalinity of, let us say, 0.09'gram of Cal) per 100 cc. bynoting the resistances corresponding to actual alkalinities asdetermined by titration.

It is impor- Changes in the electrical resistance corresponding todefinite changes in alkalinity are so utilized as to automaticallycontro amounts of CO injected in the last carbonator to bring the limedjuices within predetermined limits of alkalinity.

The appropriately carbonated juices are then treated in such manner asto effect continuous and economical separation between the solids andthe juices. The automatic and absolute control of the continuouscarbonation of the juices, whereby definitely de sired and predeterminedlimits of alkalinity are obtained, plays an important part in increasingthe particle size and settling rate of the solids.

,' Our invention will be more fully understood by reference to theaccompanying. drawings, taken in conjunction w1th the followingdescription, in which:

ig. 1 is an elevational view of the apparatus;

Fig. 2 is a plan view of the apparatus;

Fig. 3 is a sectional elevation on an enlarged scale of the temperatureregulator and electrode pot;

Fig. 4 is a schematic view of the. electrical controller and recorderapparatus and of the electrical relay circuit;

Fig. 5 is a schematic elevational view of the controller in anon-contacting position; and

Fig. 6 is a schematic elevational view of the controller in a contactingposition.

The milk of lime storage tank 1 rests upon the foundation 2. A feed line3 leads to the tank 1. A pump 4 connects the tank 1 with the pipe 5,which leads to the T 6.

' The beet iuice storage tank 7 also rests on the foundation 2. A feedsupply line 8 leads to the tank and is equiped with afloat valve 9. Thefloat 10 is so adjusted as to close the valve 9 when the tank 7 isfilled to a. predetermined level. A pump 11 connects the tank 7 with thepipe 12 which leads into the T 6. The pipe 13 leads from the T 6 to thetop of the first carbonating tank 14. A bafile 15 is located directlyunder the outlet of pipe 13 and extends to within a relatively shortdistance of the side of the tank 14, so that a space 16 is provided,between the end of the battle and the side wall of the carbonatingtank. The bottom of the carbonating tank has a conduit 17 which leads upto the normal liquid level maintained within the second carbonating tank18. A foam conduit 19 leads from the top ofthe first carbonating tank 14to the top of the second carbonating tank 18.

The second carbonating tank 18 is equipped at the top with a foamofi'take pipe 20. A conduit 21 is located at the bottom of the secondcarbonating tank and connects with a T 22.

A pipe 23 leads from the T 22 back tothe the.

pump 24 resting upon the foundation 25. This pump has a connecting pipe26 ieading up to the T 6, and is also provided with offtake pipes 27 and28 leading into the first carbonating tank 14. The/ofltake pipe 28 leadsinto the carbonating tank at a point above the normal liquid levelmaintained within the tank; while the otl'take pipe 27 leads into thecarbonating tank near the lower part thereof.

The first carbonating tank 14 and the second carbonating tank 18 restupon supports 29. These tanks are also equipped with carbon dioxide gassupplying apparatus. The gas inlet pipe 30 is equipped with an ofitakepipe 31 leading to the first carbonating tank, and an otftake pipe 32leading to the second carbonating tank. A steam pipe 33, with a controlvalve 34, connects with the oiftake pipe 31. A steam pipe 35 with acontrol valve 36 connects with the otftake pipe 32. The ofitake pipe31branches off into the four feed pipes 37 which in turn lead into thefirst carbonating tank near the bottom thereof. The portions of the fourpipes 37 Within the first carbonating tank 14 are perforated so that gasmay issue therethrough and pass up through the liquid contents of thetank.

The ofitake pipe 32 is equipped with three feed pipes 38, which insimilar manner to pipes 37, lead into the second carbonating tank 18.The portions of the pipes 38 which extend within the carbonatin'g tankare perforated so that the gas may be permitted to pass up through theliquid cofitents of this second carbonating tank.

The offtake pipe 31 has a manually operable valve 39 which may be turnedto regulate the flow of gas within the first carbonating tank. Theofftake pipe 32 is equipped with an automatic control valve 40, having agear 41, to regulate the flow of gas into the second carbonating tank.This valve is operated in such manner as to conform with variation inalkalinity of the carbonated i'uices.

A pipe 42 leads through the heater .43 (which may be heated in anyappropriate -manner such as by steam. gas or electricity) and connectswith the continuous thickener 44. A foam pipe 45 leads from the toplevel of the pipe 42 to the foam escape pi e 20, attached to the top ofthe second car onating tank 18.

A coil pipe 46 (see Fig. 3) connects with the pipe 42 and passes througha heating chamber 47 to the electrode pot 48. The heating chamber 47 hasa steam inlet pipe 49 equipped with an automatically controllable valve50. A temperature indicating bulb or coil 51 of standard make is locatedin the coil pipe 46 and is equipped with a registering conduit 53leading to the control valve 50, to automaticallyyoperate the steamvalve. An outlet pipe 55 is provided on the heating chamber 47 toconduct awa steam. The electrode pot 48' is equippe I with a d1sk 54which fits loosely in the top thereof, which disk in turn contains thefour electrodes 56 and 56. These electrodes may be made by sealing shortpieces of No. 18 platinum wire into the ends of glass tubes. The exposedportions of the wires are approximately 4" long. Two of these electrodes56 form a pair and are connected to a controller, and the other twoelectrodes 56' are connected to a resistance recorder, such asmanufactured by the Leeds and Northrup Company. The electrode pot 48rests within the overflow vessel 57, which has an outlet 58 connecting apump 59. A pipe 60 connects the pump 59 with the pipe 42 leading to thecontinuous thickener 44.

The electrodes 56 and 56' by means of lead 7 wires 61 are connected tothe controller, recorder, contact disks, relay, and automatic gas valvecontrol apparatus represented by 62 (in Fig. 2) which will be more fullydescribed below in connection with Figs. 4, 5, and 6.

The continuous thickener 44 is of the tray compartment type. The pipe 42leads into the feed chamber 63 on the top of the thickener 44. Thischamber has a foam ofltake pipe 64 for the escape of foam. An 0 ning 65leads from the compartment 63 to t e first tray compartment 66. Thecompartment 66, as well as the second compartment 67, is equipped with arevolving rake apparatus 68, appropriately connected andoperated by ashaft 69 and gearing 70, running substantial- 1y parallel to the slopingbottoms 71 of each of these compartments. Boots 72' are provided at thebottom of each of the tray compartments 66 and 67, which seal thebottoms but allow an open space from the top of each boot to the sub-jacent compartment beneath. These boots provide effective means forcollecting sludge in each individual compartment. The lower compartment73 also 45 also has the revolving raking apparatus 68, but no use ismade of a boot. Pipes 74, 75, and 76 lead respectively from near the topof the compartments 66. 67 and 7 3 to a clear liquid collecting vessel77. An outlet pipe 78 is con- 50 nected to the bottom of the collectingvessel 77.

The tops of the pipes 74, 75 and 76 are rovided with adjustable sleeves(not shown to control, or balance, the hydrostatic pressure of theescaping supernatant liquid with the hydrostatic pressuremaintainedwithin each separate compartment 66, 67 and 73. Outlet pipes 79, 80 and81 connectrespectively with the bottoms of the tray compartments 66, 67.and 73. They lead up to the pumps 82,

9 s3 and s4. 1' iThe pumps 82, 83 and 84 are in turn con- '-::&nected tothe pipe 85 leading through the heater 86 (which maybe heated by meansof steam, gas or electricity, etc.) to the continuous filter 87. I

The continuous filter 87 may be of any standard and appropriate typecommonly found on the mar et. A solids ofltake pipe 88 is provided toremove the separated solids, while the pipe 89..i s connected to thefilter in order to remove the clear juices. This continuous filter maybe of the ordinary revolving kind, in which the filter drum is made torevolve through a trough containing the sludge to be filtered. Suctionis provided on the inside of the drum to suck the clear juices from thetrough, through the filter cloths, into the filter drum; while thesolids adhere to the filter cloth, only to be forced ofi by a blast ofair or scraping action, when the drum has revolved to the desiredunloading position'.

A clear juice tank 90 is connected with the ofi'take pipe 89 from thecontinuous filter 87 and the ofitake pipe 78 from the continuousthickener 44.

All of the apparatus described, through which the juices are made toflow, are carefully insulated so that the loss of heat b rad ation maybe reduced to a minimum. l t is important that the temperature of thetreatment process be brou ht to.and maintained at appropriate leve Thetwo pairs of electrodes 56 and 56' and the terminals of the controller,recorder and relays are preferably connected according to Figs. 4, 5,and 6. in which use is made of the Wheatstone bridge principle.

The pair of electrodes 56, forms one resistance arm of vthe controllerbridge, and the other arms of the bridge are 91, 92 and 93. The bridgeemploying the pair of electrodes 56 is used in connection with thecontroller mechanism, which mechanism in turn actuates the relays insuch manner as to operate the gas control valve 40. A shunted andadjustable resistance 94 is provided adjacent to the electrodes 56 inorder to make quick readjustment to compensate for any undue changes inresistance between the electrodes. A resistance 95 is provided betweenthe transformer 96 and the'bridge arms 92 and 93 to regulate the currentsupplied to the bridge. A rheostat 98 is placed in thegalvanometercircuit to regulate the flow of current through the galvanometerwindings. A galvanome ter field coil 99 is placed. in the circuit of thetransformer96, and is rotected by the resistance coils 100 placed inseries. A key 101 is placed between thetransformer and the bridge inorder to cut-in or cut-out the current, which is taken from thealternating current supply lines 102 and 103. The coil values generallyemployed are as follows: 91, 92 and 93 equal 200 ohms each; 94 equals100 ohms; 95 is variable and depends upon the sensitivity of thegalvanometer; 98 equals 150 ohms; and 100 equals 4 to 7.5 ohms. I

The controller mechanism is preferably enclosed in a cabinet 104. Amotor 105, fed 1 from the current supplylines 102 and 103 is connectedto the controller mechanism by means of the connecting shaft 106.

The other pair of electrodes 56' is used in conjunction with therecorder mechanism. A similar Wheatstone bridge is employed, withcorresponding descriptive numbers 91', 92; 93', 94', 95', 96', 97', 98',99', 100', and 101 as used in describing the controller Wheatstonebridge. i

The controller mechanism 104 is in turn connected with contact disks 107and 108. These contact disks are operatively connected to the main shaft109 of the motor 110. The.

motor 110 gets its energy from the main current supply lines 102 and103. The disks may be appropriately geared to the main shaft of themotor in such manner as to reduce or increase the speed of the same, ascompared with the normal speed ofthe motor. The disks 107 and 108 have acontact segment 111 and 112, respectively, at the outer rim, whichcontact with the brushes 113 and 114 as the disks revolve. 'The remain--der of the disks areinsulatedto preventstraying of the current. Anappropriate current conducting wire 115 connects se ment member 111 withthe segment mem r 112. A current conductor 116 connects the main supplyline 103 with the brush 113, which brush contacts with the segmentmember 111. A current conducting wire 117 connects the controllermechanism 104 with the brush 114, which brush contacts the segmentmember 112.

'A relay mechanism is appropriately connected with the controllermechanism, as well as with the main current supply lines, and the gascontrol motor. A current conducting line 118 connects one terminal ofthe controller mechanism with the relay solenoid 119. .A spring 120 isconnected to one end of the solenoid member to keep it in a constantposition when the solenoid windings 121 are not energized.

A current conducting line 122 connects another terminal of thecontroller mechanism 104 with the relay solenoid 123. A spring 124 isconnected to one end of the solenoid member 123 to keep it in a constantposition when the solenoid windings 125 are not energized.

The solenoid member 119 is equipped with two pivoting contact brushes126 and 127; while the solenoid member 123 is eitiippled with twosimil'ar pivoting contact rus es 128 and 129. The brush 126 is sopositioned as to brush across the contacts 130 and 131; while brush 127is so positioned as to brush across the contacts 132 and 133. The brush128 is so positioned as to brush across the contacts 134 and 135; whilebrush 129 is so positioned as to brush across the contacts- 136 and 137.

The gas control valve motor 138 is provided with a motor field winding139, which nects with the leads from rate the motor in either diisadapted-to o rection depen field coil is energized. This windingconsolenoid 119; and with the contacts 134 and 137 of the solenoid 123.One terminal of the motor is connected with the main current supply line102, while the other terminal is connected to the current conductin linerunni lig between the contacts 131 an 135.-

' he "current conducting line 118, which one terminal of the controllermechanism 104, after circling around the solenoid member 119, as thesolenoid coil 121, asses to the contact 136 of the solenoid memr 123.The current conducting line 122, which. leads from another terminal ofthe controller mechanism 104, after circling around the solenoid member123, as the sole-' noid coil 125, passes to the contact 132 of thesolenoid member 119. A current conducting line connects the pivotingcontact brush 126 with the pivoting contact brush 128, as well as withthe main current supply line 103. A current conducting'line' connectsthe pivoting contact brush 127 with the ivoting contact brush 129, aswell as with the main current supply line 102.

he gas control valve motor 138 has a main shaft 140 geared at the farend 141 to mesh the gear member 41, which gear member in turn isoperatively connected to the as control valve 40. The shaft 140 is provied with a friction disk 142 operatively connected to the epivotalpoint144. The solenoid is energlz by means of the current conductingline 147', connected to terminals of the motor 138, and formin thesolenoid winding coil about the solenoif member 146; Figs. 5 and 6 areschematic views of the controller mechanism within the cabinet 104. Themotor 105 drives the shaft 106 upon which are placed the cams 157 and157 we cams are conductors of electricity, but are insulated around theshaft 106 so that stray currents cannot escape therefrom. Thegalvanometer needle 97 is so positioned that it fluctuates to the rightor left, dependin upon how the resistance between the air 0 electrodes56 varies in the Wheatstone ridge above referred to. The controllermechanism is made to rest an hinge upon the frame work 158. A rockinconnected to the frame 158 at the points 160. A rockin frame arm 161 isattached to the rocking rame 159 and it' depends to within contactingdistance of the eccentric cam 162 located on the motor shaft 106. Thiseccontacts 130 and 133 of the.

g frame 159 is pivotally mg in which direction the I centric cam is sopositioned on the shaft as to make the rocking frame 159 rise and fallas the shaft 106 is rotated. The lugs 167 provide means for stoppingtheneedle n the extreme right or left posltion. The lever arms 168 and 169are freely pivoted at the points 164 and 165. These lever arms haveextension arms 170 and 171 which extends almost halfway across the areacircumscribed by the moving galvanometer needle 97. A sufficient spacebetween the lever arm extensions 170 and 171 is provided so that thegalvanometer needle may freely restbetween them when the Wheatstonebridge 1s 1n the balanced position. The lever arms are so designed thatwhen the galvanometer needle is deflected to either the right or left,the rocking frame 159, on any of its upward movements, may lightly pressthe galvanometer needle against the lever arm extensions or 171 and thuscorrespondingly move the extreme lower ends of the lever arms 168 or 169inwardly.

A balancing arm 172 is pivoted to the member 163 and the main frame 158at the point 166, in a freely movable position. Contact lugs 173 and 174are attached to either end of the balancing arm 172, so as to just fail'to brush across the current conducting cams 157 and 157', when thebalancing arm is in its normally horizontal and balanced position. Theselugs are current conductors and are insulated from the balancing member172 by means of the non-conducting material 175 placed between the lugsand the balancing member. These lugs are in turn connected to thecurrent conducting wire 117, which wire is attached to the'brush 114 atdisk 108.

A freely movable frame 176, with lugs 177 and 178, is freely pivoted atthe point 166, in working position with the lever arms 168 and 169. Thisframe forms a rigid part of the balancing arm 17 2, so that when thelugs 178 or 177 are pressed by the lever arms 169 or 168 respectively,the balance arm 172 will be relatively moved in its clockwise oranticlockwise, position.

Contact brushes 179 and 180 are so positioned as to make contact withthe current conducting cams 157 and 157 as the cams revolve with andabout the motor shaft 106. The brushes are also connected to the currentconducting wires 118 and 122, which lead to the relay mechanism abovedescribed.

The recorder mechanism 181 is of a standard type used for ordinaryrecording purposes of this kind. It is operated by means of the shaft182 connected to the motor 183. This recorder motor is fed by currentfrom the main current supply lines 102 and 103.

The operation is as follows:

Milk of lime from storage tank 1, and raw diffusion beet juices from thestorage tank 7, both of which have been preliminarily heated, areconducted by means of pum 4 and 11 to join each other in the T 6., T eintermingled milk of lime and beet juices thereupon fiow togetherthrough pipe 13 onto the baffle 15. This bafiie 15 is so positionedwithin the first carbonator tank 14 that the combined juices may trickledown the side wall of the carbonator .tank through the space 16, betweenthe carbonator wall and the baflle itself. This is done in order tocause as little agitation of the juices as possible, thus preventing anyundue formation of foam. 1

As the carbonator tank 14 graduall fills up with the combined milk oflime an beet juices, 9. art of the mixture is forced by way of the pipe17 from the bottom of the first carbonator tank 14 into the secondcarbonator tank 18. The inlet level ofthe ipe 17 in the secondcarbonator tank is at t e normal liquid level of the two carbonatortanks.

Any foam that is formed within the first carbonator tank 14 is permittedto pass over to the second carbonator tank 18 by way of pipe 19. A partof this foamwill disintegrate into uices within the second carbonatortank, and whatever foam is not precipitated is permitted to pass upthrough the foam outlet pipe 20.

A gas containing carbon dioxide is fed through the supply pipe 30 andbranches off to the first and to the second carbonator tanks. The carbondioxide gas passing to the first carbonator tank 14 by way of pi e 31 isbrought to a desired temperature by means of steam supplied through pipe33 and controlled by valve 34. The mixture of carbon dioxide gas andsteam are thereupon sub-divided into four main divisions by means ofpipes 37. The gas is then permit-ted to escape through the perforationswithin the parts of the pipes 37 extending into the first carbonatortank. The gas bubbles up through the body of juices. The chemicalreaction, Ca (OH) 2 CO CaCO H O takes place. Any excess gas escapes withthe foam through pipe 19 into the second carbonator tank.

The gas branching from pipe 30 through pipe 32 is likewise heated bymeans of steam,

the steam being supplied through the pipe 35 and regulated by the valve36. The mixture of carbon dioxide gas and steam is conducted togetherfor a short distance, and it is then sub-divided into three main streamsby means of the pipes 38. The gases are permitted to bubble up throughthe body of liquid within the second carbonator tank, by passing throughthe many perforations within those portions of the pipes 38 extendingwithin the carbonating tank. Any excess gas escaping from the body ofjuices is permitted to escape with the foam up the stack 20.

The amount of gas admitted to the second carbonator tank isautomatically controlled Within predetermined limits b means of thevalve 40, which will be more ully explained below. 1

If the juices within the second carbonator tank have not been given asuflicient amount of gas, or in fact have been given too much gas, thejuices may be recirculated by way of ipe 23 and pump 24 back into thefirst car onator tank. Valves and piping are so arranged that therecirculated juices ma be admitted near the bottom of the first carnator tank by way of pipe 27, or above the normal liquid level of thefirst carbonator tank by means of pipe 28.

Since it is advantageous to increase the particle size of the calciumcarbonate, 02100,, in order to make the subsequentsteps of thickeningandfiltering more efiicient, large portions of the gassed contents of thesecond carbonator tank are recirculated back to the first carbonator. Wehave found it advan-' tageous to recirculate about six volumes from thesecond carbonator tank, to the first, carbonator tank, to one volume offresh combined beet juices and milk of lime, initially introduced intothe first carbonator tank. The particles of CaCO which are transferredfromthe second carbonator tank'to the first carbonator tank induceparticle growth. That is to say, freshly precipitated CaCO in the firstcarbonator tank adheres to and becomes part of particles of CaCOcirculated from the second carbonator tank back to the first carbonatortank.

The completely gassed contents of the second carbonator tank are flowedby way of pipe 42 through the heater 43 into the continuous thickener44. As the treated juices are thus passed to the thickener, a relativelysmall test portion is withdrawn 'from the pipe 42 through the pipe 46,and is preheated to a'predetermined temperature. This test portion thenpasses into the electrode pot 48 where the electrical resistance betweenthe b pairs of electrodes 56 and 56' are appropriately measured. Sincethe electrical resist ance between these electrodes is inverselyproportionate to the alkalinity of the test portion, use may be made ofthis relationship to automatically control the amount of CO gas admittedto the second carbonator tank by way of the automatic gas valve 40. Thetest portion which continuously flows into the electrode pot 48gradually overflows the same into the collecting chamber 57. The pump 59continuously passes the overflowing test portion back into the line 42by way of pipe 60.

It is very important that the test portion be taken at a point wellremoved from the zone of chemical and dissolution reactions within thecarbonating tanks. The reaction that takes place within the lastcarbonator tank between the CO and the Ca-(OH) is so rapid that theconcentration of Ca (OH) in true solution is reduced below the value itwould have if the gas were momentaril cut off and the remainmgundissolved Ca( H) were allowed to pass into solution. If the testportion is taken well removed from the zone of active reaction, completesolution of the soluble Ca(OH) will have occurred before the juicesreach the electrode pot.

The previously heated bodies of juices have cooled down somewhat by thetime they reach the continuous thickener. For that reason the heater 43is interposed between the second carbonatortank and the continuousthickener, so that the temperature of the combined juices and' solidsmay be raised to the temperature found consistent with efiicient andrapid thickening. Of course the use of this heater is optional,particularly if the previously gassed liquids have not appreciablyfallen in temperature. Any foam which may have found its way into pipe42 or formed within the pipe 42 is allowed to escape by way of pipe intothe foam outlet stack 20.

The combined juices and solids are'flowed into the receiving chamber 63of the continuous thickener 44. These find their way down through theoutlet 65 of the first tray compartment 66' As this compartmentgradually fills up, part of its contents pass to tray compartment 67,and ultimately to tray compartment 73. The rakes 68 are set in motion bythe shaft 69, to which they are attached, which is made to revolve by amotor (not shown). As the solids settle to the bottom ofthe sloping traycompartment, the rakes 68 gradually carry the solids toward the centerof the compartment, whereupon the solids are continuously withdrawnthrough the pipes 79, 80, and 81 by 82, 83, and 84, respectively.

The clear juices, .on the other hand are withdrawn from near the top ofthe individual tray compartments by means of the pipes 74, and 76 intothe collecting chamr 77. The clear juice is then permitted to flow byway of outlet 78 into the clear juice collecting tank to await furtherprocess treatment used in the manufacture of sugar, such'as outlinedabove.

The sludge which has been pumped from the continuous thickener by meansof the pumps 82, 83 and 84 is flowed into the pipe 88 which passesthrough the heater 86. Since appropriately heated materials will moreeasily lend themselves to filtering, we have found it advisable topreheat the sludge before it enters the filterer, particularly if thereis a substantial drop of the thickening operation. heater is optional.

The preheated sludge is then passed into the continuous filter 87, wherethe remaining clear juices are finally separated from the solids. Thesolids escape by way of outlet pipe 88, while the clear juices areconducted The use of this means of the pumps temperature during throughthe outlet pipe 89 to the clear juice collecting tank 90 to awaitfurther process treatment.

The beet juiceclarification treatment operation of the invention hasjust been described, and it now becomes necessary to explain theoperation of the automatic control features ofourdiscovery, which aregraphyically illustrated in Figs. 3, 4, and 6.

Variations in the resistance of the test portion between the electrodes56, by means of the' well known Wheatstone bridge principle, areregistered by variations in 'the swing of the galvanometer needle 97.For example, if the bridge is perfectly balanced (i. e., when theresistance arms 91, 92 and 93 and the resistance between the electrodes56 areall equal to one another), the galvanometer coil will not beenergized and the needle 97 will consequently not be deflected.

If the resistance between the electrodes becomes greater than that ofits'corresponding resistance arm, current will be forced throu h thegalvanometer coil in one direction and t e needle will bedeflected, letus say, to the left.

If the resistance between the electrodes be-- I galvanometer needle 97has been deflected to the left (as shown in Fig. 5) The motor whichcontinuously drives the shaft 106 also makes the cams 157 and 157revolve continuously. These revolutions take place'at intervals ofapproximately 6 seconds each.

For each revolution the eccentric cam 162 strikes the rocking framemember 161 which in turn forces the rocking frame 159 up against thebottom of the galvanometer needle. This movement of the rocking framepushes the top of the galvanometer needle against the bottom ofthe'lever arm extension 170, whereupon the lever arm 168,- which ispivoted at point 164 bears over to the ri ht and strikes against the lug177. Since t is lug and its frame 176 are rigidly attached to thebalance arm 172, the balance arm is swung away from. its normallyhorizontal position; and the contact lug 173 is forced downward, whilethe opposite contact lug 174 is swung upward. The eccentric cam 162 verysoon releases the rocking frame 159, and the galvanometer needle is atonce free to move in any direction in response to any new changes inalkalinity which may in the meanwhile have taken place in the testportion, and which has correspondingly afiected the resistance betweenthe electrodes 56.

As the cams 157 and 157? are revolved, earn 157 gradually brushesagainst the contact lug 1 4 and forces it down into its normallyhorizontal position, while the opposite conductor being :.the currentconducting wire 117, the contact in 174, the current conducting cm 157,the rush 180, and the current conducting line 122.

It is quite apparent that if the galvanometer needle 97 is swung in therighthand direction, that the operation of the mechanism shown in Figs.5 and '6 will be reversed; and that the cam 157 will this timebrushagainst the contact lug 173,- whereupon current .may pass through thecurrent conducting line 117, the contact lug 173, the current conductingcam 157, the" brush 179, and the current conducting line 118.

Suppose on the other hand, that the Wheatstone bridge does notbecomeunbalanced, due to the exact conditions of alkalinity maintained in thetestportion, the galvanometer needle 97 will not deflect either to theright or to the left. The eccentric cam 162 will nevertheless force therocking frame up against the galvanometer needle; but, since a space isprovided between the lever arm extensions and 171 sufficiently large toallow for the free up and down movement of the galvanometer needle, itis apparent that the lever arms 168 and 169 will not be moved; and,conseguently, that the balance arm 172 will thereore continue in itsnormally horizontal position. When this takes place, neither the cam"157 nor the cam 157' will brush against the contact lugs, and therewill therefore be no conductor provided for carrying the alternatingcurrent from the current supply line 117 to the current supply line 122,or back again.

Every time the cams 157 and 157' are revolved and make contact with thecontact lugs 173 or 174, the automatic gas control valve 40 wouldnormally be correspondingly opened or closed to control the amount of COgas admitted into the second carbonator tank. Suchfrequent changes (onceevery 6 seconds) in the amount of CO gas admitted to the secondcarbonator tank would obviously be inadvisable, because after such achange has been made a considerable time elapses before the alkalinityof the juices coming from the second carbonator tank shows a changecorresponding to the change in the amount of gas admitted. For thisreason, it is desired to turn the valve 40 less frequently, and it hasbeen found that about 100 seconds should be allowed between chan es ofthe gas valve to make sure that the in l efiect of one change has beenobtained before another one is made. In orderto utilize the 6 secondsinterval action of the controller mechanism just de scribed, but at thesame time to modify its ultimate effect on the control valve 40, pro-'vision has been made to make the valve changes at 100 second intervalsby means of lo the contact disks 107 and 108 in cooperation withmovements of the controller mechanism. The motor 110 is fed from themain current supply lines 102 and 103. An appropriate gearin not shown,may be used in conjunction wlth the driving shaft 109 to slow or speedup the disks 107 and 108. These disks have contact segments. 111' and112, which can be so positioned relatively to one another as to lengthenor retard the time of simultaneous contact with the brushes 113 and 114.The alternating current passing through the contact disks is takendirectly from the main current supply line 103, and through the currentsupply line 117 which is intimately associated with the controllermechanism just described above, as well as the relay system now to bedescribed. Although the controller mechanism revolves once every 6seconds, there can be no passage of current through the cams 157 and157' until the brushes 113 and 114 brush against the contact segments111 and 112 during the interval that these brushes are simultaneouslypressing against their corresponding contact segments, and the currentpasses through the current conducting line 115 connecting the twocontact segments.

Let us again assume that the galvanometer needle 97 has been deflectedto the left (as shown in Fig. 5) the cam 157 will then brush against theraised contact lug 174 and thus form a conductor between the currentconducting lines 117 and 122. If at the time that the cam 157 brushesagainst the lug 174. the brushes 113 and 114 simultaneously bear againstthe contact segments 111 and 112 of the contact disks 107 and108,current will pass from the main current supply line 103 through 116,through brush 113, segment 111, current conducting line 115, segment112, brush 114, line 117, lug 174, cam 157 brush 180, and line 122 whichwinds its way through the relay circuit back to the main current supplyline 102. It is thus seen that a complete current conducting line hasbeen provided between the main current supply line 102 (through thecontact disks, the controller mechanism, and the relay mechanism) andthe other main current supply line 103, or vice versa. I

Assuming that the galvanometer needle 97 has been deflected to theright, that is in the opposite direction, it will be apparent that cam157 will then brush against the now raised contact lug 173. If atthesame time 85 the brushes 113 and 114 are simultaneously bearing againstthe contact segments 111 and 112 of the contact disks 107 and108,'current' will again alternate between the current sup ply lines 103and 102 as just described. In this situation, however, the currentsupply line 118 will be substituted for the current vided between themain current supply line 102 (through the contact disks, the controllermechanism, and the relay mechanism) and the other main current supplyline 103, or vice versa.

In order to follow the operation of the relay mechanism, let us againsuppose that the galvanometer needle 97 has been deflected to the left(as shown in Fig. 5) and that the controller mechanism and the contactdisks are simultaneously in such a position as to allow current toalternately pass completely through the system. As the current passesdown through the line 122 and through the solenoid coils 125, thesolenoid core 123 is pulled to the left. The current passes to thepivoted brush 127 at the contact lug 132, and passes from thence back tothe main current supply line 102. As the solenoid core 123 is pulled tothe left, the pivoted contact brush 129 is swung over to the contact lug137, which then provides a current conductor from the main currentsupply line 102, through contact 137, through the field winding 139 ofthe gas valve control motor 138. The current continues from the fieldwinding of the motor up to the contact lug 130, through the pivotedbrush 126, and from thence back to the other main current supply line103. Since the motor windings are energized by connecting one terminalof the motor with the main current supply line 102 and the other motorterminal with the relay circuit connecting the lugs 131 and 135 (whichlatter line is dead when the solenoids are in their normal position;that is, when they are not energized) The energizing of the motor fieldwinding 139 will make the motor revolve in one direction, withconsequent turning of the gas valve in a corresponding direction.

If we now assume that the galvanometer needle has been deflected to theright, and the cam 157 contacts with the now raised lug 123, as thebrushes 113 and 114 Simultaneously bear against the contact segments 111and 112 of the contact disks 107 and 108, current will pass down throughthe line 118 to the solenoid coil 121 of the solenoid 119. The currentpasses through the solenoid coil 121 30 to the contact lug 136, throughthe pivoted brush 129, and from thence back to the main ftrolled withindesired and current supply line 102. During the assage of the currentthrough this circuit, t e solenoid member 119 is energized in suchmanner as to draw the solenoid core to the right. When this takes-placethe pivoted brush 127 swings over to the contact lug 133. As soon as 4this takes place, current passes from the main current supply line 102down through the pivoted brush 127, the contact lug 133, and the motorfield winding 139, contact lug 134, the pivoted brush 128, and fromthence back to the other main current supply line 103.

We therefore see that the motor field windinghas been energized in adirection opposite to the one described above, when the galvanom-' eterneedle was swung in the opposite direction, and the motor will thereforerun in the opposite direction, and reverse the operation of the gascontrol valve 40. a

In order that the operation of the gas control valve may be quicklystopped as soon as the relay'circuit solenoids have gone back to theirnormal position, provision is made for quickly stopping the motor,instead of letting it gradually die down, as it normally would. Themotor shaft 140 is provided with a friction disk 142, over and uponwhich an appropriate brake 143 is placed; As soon as current has passedthrough the terminals of the motor, the brake solenoid coil 147 isenergized and the solenoid member 146 is pulled upwardly. This upwardmovement of the solenoid lifts the brake freely above the friction disk142, and there is no brake action. The motor maythen freely rotate. Assoon as the relay circuit solenoids have been brought back to theirnormal position, by means of the springs 120 or 124, the current nolonger flows through the motor terminals and the solenoid windings 147are thereupon de-energized. The spring 145 thereupon draws the braketightly down upon the friction disk 142, about the pivotalpoint 144, andthe motor is quickly stopped.

Therecorder mechanism 131 is of a standard type, and it merely recordsin a conventional way the variations in resistance between theelectrodes 56' as determined by the differences in alkalinity from theset standinvention we are able to continuously treat sugar ulces 1n themanufacture of sugar under automatically controllable conditions. Thisrepresents a step far in advance over the usual batch methods oftreating such sugar containing juices now generally employed in themaking of sugar.

tion taken from the b0 The alkalinity of the carbonated juices is notonly continuously and automatically conlimits but the completely car'onated juices are likewise subjected to continuous se ara-,

able by batch methods, and thus increase the settling and filtering rateof the solids. The density'to which the solids will settle represents anincrease of about 100% over that obtained under batch operations. Wehave also found that we can continuously filter our continuously treatedjuices about 20% faster than under the old batch system heretoforeemployed. y We claim:

1. A method of treating juice in the manufacture of sugar whichcomprises continuously flowin together sugar juice and milk of hme, subecting the body of limed juice to carbon dioxide gas, measuring theelectrical resistance of a representative test pory of limed juiceundergoing carbon dioxide treatment at a point removed from the zone ofchemical and dissolution reactions, and automatically controlling theamount of carbon dioxide gas passed into the body of limed juice asmeasured by said electrical resistance to- 2. A method of continuouslytreatin juice in the manufacture of sugar whic comprises flowingtogether approximately uniform volumes of su ar juice, and milk of lime,passing said lime 'ulce through a plurality of connecting bod ies,separately subjectin the limed ju1ce to carbon dioxide gas in eac body,measuring the electrical resistance of a representative test portiontaken from the last body at a point removed from the zone of chemicaland dissolution reactions, automatically controlling the amount ofcarbon dioxide gas passed into the last body of juice to bring the samewithin predetermined limits of alkalinity by an action responsive tochanges in said electrical resistance, and constantly removing thecarbonated juice.

3; A method of carbonatin limed juice in the manufacture of sugar w ichcomprises, subjecting a series of connected bodies of the limed juice tocarbon dioxide gas, recirculating carbonated juice from a later to anearlier body of the series, automatically regulatmg the amount of carbondioxide gas injected into the last body of limed juice in the series byutilizing changes in the electrical resistance of a test portion takenfrom the last 'body undergoing carbon dioxide redetermined treatment ata point removed from the zone of chemical and dissolution reactions tomaintain said last body of juice within determined limits of alkalinity.

4. A method of carbonating juice containing compounds of lime and sugarwhich comprises, subjecting a series of connected bodies of the limedjuice to carbon dioxide gas, automatically regulating the amount ofcarbon dioxide gas injected into the last body of limed juice in theseries by utilizing changes in the electrical resistance of a testportion taken from the body undergoing carbon dioxide treatment at apoint removed from the zone of chemical and dissolution reactions tomaintain said last body of juice within predetermined limits ofalkalinity.

5. A'method of carbonating limed juice in the manufacture of sugar whichcomprises subjecting the limed juice to carbon dioxide gasin acarbonation zone with the proportioning of the juice and gas controlledin amount to bring the juice within predetermined limits of alkalinity,said control being effected by measuring the electrical characteristicsof a representative test portion taken from the body of the limed juiceundergoing carbon dioxide treatment after the dissolution of the limehas gone to completion, utilizing changes in the electricalcharacteristics of said test portion to maintain the carbonatedjuiceWithin predetermined limits of alkalinity, and recirculating thecarbonated juice to increase particle growth of the solids.

6. A method of continuously carbonating limed juice according to claim5, which comprises continuously fiowing limed juice into the carbonationzone, repeatedly returning portions of the juice to the carbonation zonein order to encourage particle growth of the solids, and continuouslywithdrawing carbonated juice from the zone.

7. A method of carbonating juice containing compounds of lime and sugarwhich comprises subjecting a series of connected bodies of the limedjuice to carbon dioxide gas, recirculating carbonated juice from a laterto an earlier body of the series, automatically regulating the amount ofcarbon dioxide gas injected into the last body of limed juice in theseries by utilizing changes in the electrical resistance of a testortion taken from the body undergoing car on dioxide treatment after thedissolution of lime has gone to completion to maintain said last body ofjuice within predetrmined limits of alkalinity.

23. A method of carbonating limed sugar juiceto obtain maximumcoagulation of 1 purities therein which consists in mixin sugar juiceand lime countercurrently with carbon dioxide gas while maintaining themixture alkaline, completing chemical reaction between the lime andjuice, completing dissolution of unreacted lime and juice, circulating aportion of the carbonated juice after said, reactions have beencompleted through a sampling zone, and automatically electricallyindicating the degree of alkalinity of the carbonated juice in saidzone.

9. A method of carbonating limed sugar juice to obtain maximumcoagulation of 1mpurities therein which consists in mixing sugar juiceand lime countercurrently wit carbon dioxide gas while ma1nta1n1ng themixture alkaline, completing the chemical and physical reactions etweenthe lime and juice, circulating a portion of the carbonated juice aftersaid reactions have been completed through a sampling zone continuouslyindicating the degree of alkalinity of the carbonated juice 1n said zoneand using said indication to electrically operate a control of theproportion of gas and juice being mixed.

10. A method of carbonating limed sugar juice to obtain maximumcoagulation OflIIlpurities therein which consists in mixing sugar juiceand lime countercurrently with carbon dioxide, gas While maintaining thet es.

ur ELMER R. RAMSEY.

ARTHUR w. BULL.

